The traditional monolithic RF base transceiver station (BTS) architecture is increasingly being replaced by a distributed BTS architecture in which the functions of the BTS are separated into two physically separate units—a baseband unit (BBU) and a remote radio head (RRH). The BBU performs baseband processing for the particular air interface that is being used to wirelessly communicate over the RF channel. The RRH performs radio frequency processing to convert baseband data (referred to as basedband IQ data below) output from the BBU to radio frequency signals for radiating from one or more antennas coupled to the RRH and to produce baseband data, e.g., baseband IQ data, for the BBU from radio frequency signals that are received at the RRH via one or more antennas.
The RRH is typically installed near the BTS antennas, often at the top of a tower, and the BBU is typically installed in a more accessible location, often at the bottom of the tower. The BBU and the RRH are typically connected through one or more fiber optic links. The BBU operates on digital baseband data, interfacing to the RRH, which provides the radio frequency (RF) transceiver functionality to convert from baseband to RF and vice versa. The RRH typically has multiple antenna ports for interfacing to multiple base station antennas for diversity and MIMO operation. The interface between the BBU and the RRH is defined by front-haul communication link standards such as the Common Public Radio Interface (CPRI) family of specifications, the Open Base Station Architecture Initiative (OBSAI) family of specifications, and the Open Radio Interface (ORI) family of specifications. The different front-haul communication link specifications define a control and management (C&M) plane and a user-plane. The C&M plane carries all the control, management, and maintenance data and the user-plane carries the baseband IQ data. When the BBU is configured for LTE MIMO configurations, the baseband IQ data for the different antenna ports is sent on multiple baseband IQ data streams in the user-plane and the C&M plane is used to associate each baseband IQ data stream with the correct antenna port of the RRH.
However, the C&M channel is typically vendor-specific and proprietary. As a result, the association information in the C&M plane that is used by the RRH to associate each baseband IQ data stream with an antenna port is not easily available to other devices or systems that use the baseband IQ data streams and need to know with which antenna port each baseband IQ data stream is associated.